JPH09258211A - Rear projection type liquid crystal projector device - Google Patents

Abstract

A rear projection type liquid crystal projector device having a wide dynamic range of image brightness and improved contrast. SOLUTION: Substantially parallel light obtained from a light source lamp 111 and a parabolic mirror 115 is decomposed and combined into an optical path for each of three primary colors of light by a dichroic mirror and a reflecting mirror. An optical shutter composed of a polarizer, a liquid crystal panel and an analyzer is inserted in the optical path for each color to form an image from a video signal, the images are recombined and projected onto a screen by a projection lens. The screen is a Fresnel lens 175, a lenticular lens 17
7 and the polarization film 13, the polarization direction of the polarization film 13 is
It is aligned with the polarization direction of each analyzer. Further, the displacement mechanism 15 that rotates or tilts the polarizer 155 and the analyzer 165 with respect to the liquid crystal panel 145 while maintaining the mutual positional relationship adjusts the intensity of the green light transmitted through the polarizing film 13 to adjust the color temperature. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection device for magnifying and projecting a reproduced image of a television or the like, and more particularly, to rear projection for projecting an image from the back side of a screen by using a liquid crystal panel as an optical shutter for image reproduction. Type liquid crystal projector device.

[0002]

2. Description of the Related Art Following high-definition broadcasting, terrestrial television broadcasting has also started to be broadcast on a wide screen. Also, with the spread of cable television, the upcoming digital television broadcasting, and the introduction of high-resolution software such as digital video discs, a high-quality large-screen image reproducing apparatus is desired.

However, the CRT used in the conventional direct-view display device has a limit of about 40-inch due to the manufacturing technology, manufacturing cost, size and weight of the product, and the like. Alternatively, there is a rear projection type projector system. Further, these projector systems have a CRT system and a liquid crystal system, respectively, depending on the device that forms the original screen to be enlarged and projected, and although the liquid crystal projector is inferior in the maximum brightness as compared with the CRT projector, the focus performance and the device It is considered to be excellent in terms of size and weight reduction.

FIG. 8 is a system configuration diagram showing an outline of a conventional three-panel rear projection type liquid crystal projector device. In the figure, a conventional rear projection type liquid crystal projector device 101 is shown.
Is a light source lamp 111 serving as a light source, and the light source lamp 111
A power supply circuit 113 for supplying power to the light source;
UV / IR filter 11 that cuts ultraviolet rays and infrared rays
7, dichroic mirrors 121, 123, 133, 135 and a total reflection mirror 12 which constitute color separation / combination means.
5, 131, liquid crystal panels 141, 143, 145 provided for the respective color-separated light paths, and polarizing plates 151, 1 serving as polarizers provided on the light incident side of each liquid crystal panel.
53, 155, polarizing plates 161, 163, 165 serving as analyzers provided on the light emission side of each liquid crystal panel, and a projection lens 171 for enlarging and projecting the color-combined light.
A Fresnel lens 175 and a lenticular lens 177 which are screens, a video input terminal 181 to which a video signal is input, and liquid crystal panels 141 and 143 from the video signal.
And a signal processing circuit 183 for generating a drive signal for driving the drive circuits 145.

The operation of the conventional rear projection type liquid crystal projector device 101 is as follows. First, a light source lamp 1 using a halogen lamp, a metal halide lamp, etc.
11 receives light from the power supply circuit 113 and emits light. The light emitted from the light source lamp 111 is parabolic mirror 1
The light is controlled and reflected by the light beam 15 into substantially parallel light that is emitted to the right. From the substantially parallel light obtained from the parabolic mirror 115, wavelengths in the ultraviolet and infrared regions which are unnecessary and harmful to image formation are U
It is cut by the V / IR filter 117.

Next, 45 ° with respect to the optical path of the substantially parallel light.
By means of the dichroic mirrors 121 and 123 which form a part of the color separation / combination means arranged at an angle of, for example, blue light (hereinafter abbreviated as B), red light (hereinafter abbreviated as R) and green light (hereinafter abbreviated as G). ), The optical paths of the three primary colors of light are separated.

That is, first, the dichroic mirror 1
B is reflected and separated by 21 and then R is reflected and separated by the dichroic mirror 123.
The remaining G enters the liquid crystal panel 145 via the polarizing plate 155.

B is reflected by the total reflection mirror 131 and is incident on the liquid crystal panel 141 through the polarizing plate 151. R is incident on the liquid crystal panel 143 via the polarizing plate 153. The B, R, and G lights to which the liquid crystal panels 141, 143, and 145 are provided with the optical rotatory power corresponding to the video signals, are polarizing plates 161, 163, which are analyzers provided on the emission side of the respective liquid crystal panels. After the optical rotatory spatial distribution is converted to a light intensity spatial distribution by 165, the reflecting mirror 1
25 and the dichroic mirrors 133 and 135 perform color combination and enter the projection lens 171.

The Fresnel lens 175 is the projection lens 17
The light emitted from the light source 1 is focused on the observation position, and the lenticular lens 177 controls and / or diffuses the light passing through the Fresnel lens 175 in an arbitrary direction.

On the other hand, based on the video signal input to the video input terminal 181, the signal processing circuit 183 generates a drive signal for controlling the optical rotatory power of each cell of the liquid crystal panels 141, 143 and 145, and these liquid crystals are generated. Supplied to the panel.

The rear projection type liquid crystal projector device 101 is housed in a casing (not shown) in which the front surface of the lenticular lens 177 is exposed, and an image is displayed by an observer from the right side of the lenticular lens 177 with reference numeral 191. To be observed.

In such a conventional rear projection type liquid crystal projector device, there is a device for improving the contrast by utilizing the fact that the light passing through the optical shutter composed of the liquid crystal panel and the polarizing plate is linearly polarized light. There wasn't.

Further, it is known that at least one reflecting mirror is provided between the projection lens and the Fresnel lens and the optical path from the projection lens to the screen is bent by the reflecting mirror to downsize the rear projection type liquid crystal projector device. However, there is no such device that uses S-polarized light that has a high reflectance and obtains a bright image by utilizing the difference in reflectance depending on the polarization direction on the reflecting surface of the reflecting mirror.

Further, in the conventional rear projection type liquid crystal projector device, the color tone of the image reproduced is set to a predetermined correlated color temperature (for example, the reference value of the correlated color temperature of white for high-definition vision determined by CCIR in 1990 is , 6500 K. Hereinafter, when the correlated color temperature is simply abbreviated as “color temperature”), or when the color temperature is set according to the preference of the expression color due to the climate and the custom of the product shipping destination, ethnic customs,
A signal for color temperature adjustment is added to a luminance signal corresponding to a pixel, which is input to each liquid crystal panel for each of the three primary colors.

[0015]

However, compared with the front projection type liquid crystal projector device, the conventional rear projection type liquid crystal projector device can see an image without darkening the room. However, there is a problem that the black level of the image rises because of the reflection on the screen, and the contrast of the image decreases according to the ambient brightness.

Further, in the above-mentioned conventional rear projection type liquid crystal projector device, compared with the central portion of the screen, the light intensity and the contrast at the peripheral portion of the screen, particularly at the four corners of the screen are remarkably lowered, and the image at the peripheral portion of the screen is difficult to see. There was a problem.

Further, in the conventional rear projection type liquid crystal projector device, since the color temperature adjusting signal is added to the luminance signal corresponding to the pixel which is input to each liquid crystal panel for each of the three primary colors, each liquid crystal panel itself. There is a problem that the dynamic range for displaying an image is reduced from the luminance gradation of, and the fidelity of a reproduced image is reduced. The present invention has been made in view of the above problems, and its main problem is to provide a rear projection type liquid crystal projector device which is improved so as to reduce a decrease in contrast with respect to external light as compared with a conventional device. Is to provide.

Another object of the present invention is to provide a rear projection type liquid crystal projector device in which the contrast at the peripheral portion of the screen, particularly at the four corners of the screen is improved.

Another object of the present invention is a rear projection type liquid crystal projector device in which the optical path from the projection lens to the screen is bent by a reflecting mirror to make it compact, and the polarization direction of the light incident on the reflecting mirror is adjusted to be high. It is an object of the present invention to provide a rear projection type liquid crystal projector device that can utilize reflectance.

[0020]

To achieve the above object, the present invention has the following constitution. That is, the invention according to claim 1 is a light source lamp, a parabolic mirror that controls and reflects light emitted from the light source lamp into substantially parallel light, a substantially parallel light obtained from the parabolic mirror, and a dichroic mirror. A color separation / combination means that separates into different paths for each of the three primary colors of light using a total reflection mirror and then re-combines them, and is provided for each path of the light separated into these three primary colors, and arranged in a matrix. Three liquid crystal panels provided with a plurality of liquid crystal cells, a polarizer provided on each light incident side of these liquid crystal panels, and a light emission side provided on each of these liquid crystal panels. An analyzer, a projection lens for enlarging and projecting the color-combined light, and a Fresnel lens for condensing the light emitted from the projection lens at an arbitrary position,
In a rear projection type liquid crystal projector device comprising a lenticular lens for controlling and / or diffusing light passing through the Fresnel lens in an arbitrary direction, the rear projection type liquid crystal projector device is arranged at an arbitrary position from the projection lens to the front surface of the lenticular lens. While maintaining a mutual positional relationship with a polarizing film having the same polarization direction transmission characteristics as the analyzer and the polarizer and the analyzer provided on the incident side and the emitting side of at least one liquid crystal panel as a pair, A rear projection type liquid crystal projector device further comprising a displacement mechanism for rotating or tilting the liquid crystal panel.

According to a second aspect of the present invention, a light source lamp, an ellipsoidal mirror for reflecting and condensing light emitted from the light source lamp, and light emitted from the ellipsoidal mirror are substantially parallel to the optical axis. And a color separation / combination means for recombining substantially parallel light obtained by the condensing lens into different paths for each of the three primary colors of light by using a dichroic mirror and a total reflection mirror. , Three liquid crystal panels provided for each of the paths of the light separated into the three primary colors, each including a plurality of liquid crystal cells arranged in a matrix, and provided on the light incident side of each of the liquid crystal panels. Polarizer, an analyzer provided on the light emission side of each of these liquid crystal panels, a projection lens for magnifying and projecting the color-combined light, and the light emitted from this projection lens at an arbitrary position. Focus on In a rear projection type liquid crystal projector device comprising a Fresnel lens and a lenticular lens for controlling and / or diffusing light passing through the Fresnel lens in an arbitrary direction, an arbitrary distance from the projection lens to the front surface of the lenticular lens is provided. A polarizing film having the same polarization direction transmission property as that of the analyzer disposed at a position and the polarizer and the analyzer provided on the incident side and the exit side of at least one liquid crystal panel are paired to maintain a mutual positional relationship. However, the rear projection type liquid crystal projector device further includes a displacement mechanism for rotating or tilting the liquid crystal panel.

According to a third aspect of the present invention, in the rear projection type liquid crystal projector device according to the first or second aspect, the polarizing film is arranged outside the lenticular lens, and further outside the polarizing film. The gist is that a light transmitting plate having an arbitrary transmittance is further provided.

According to a fourth aspect of the present invention, in the rear projection type liquid crystal projector device according to the first or second aspect, the polarizing film is arranged outside the lenticular lens, and the lenticular lens and the polarizing film are provided. The gist is that a light transmission plate having an arbitrary transmittance is further provided between and.

According to a fifth aspect of the present invention, in the rear projection type liquid crystal projector device according to any one of the first to fourth aspects, a reflecting mirror is further provided between the projection lens and the Fresnel lens. The polarization direction of the light emitted from the projection lens is S-polarized with respect to the reflecting mirror.

In the rear projection type liquid crystal projector device according to the present invention having the above-mentioned structure, the polarized light which selectively passes only the light in the same polarization direction as the analyzer to an arbitrary position from the projection lens to the front surface of the lenticular lens. By further including the film, when the light passing through the analyzer is observed as an image through the lenticular lens, only the light having the same polarization direction as that of the analyzer is selectively passed by the polarizing film. The light that carries the image is not attenuated and the component perpendicular to the polarization direction of the polarization film of the light incident from the outside of the rear projection type liquid crystal projector device is prevented from being reflected and passed by the polarization film. The dark areas become darker and you can see the image with improved contrast.

Further, according to the present invention, the polarizer and the analyzer provided on the incident side and the exit side of at least one liquid crystal panel are paired and rotated with respect to the liquid crystal panel while maintaining the mutual positional relationship. Alternatively, since a displacement mechanism for inclining is provided, for example, color separation into three primary colors of light R, G, and B is performed, an image is reproduced by a liquid crystal panel provided corresponding to each color, and this image is color-synthesized. When reproducing a full-color image, it is possible to adjust the color temperature by attenuating the high-intensity color component by the displacement mechanism, so that the drive circuit of the liquid crystal panel is simplified and the brightness gradation of the liquid crystal panel is reduced. Images can be displayed without devoting to color temperature adjustment, and faithful images with a wide dynamic range can be reproduced.

In the present invention, a polarizing film is arranged outside the lenticular lens, and a light transmitting plate having an arbitrary transmittance is arranged further outside the polarizing film.
Furthermore, it is possible to improve the contrast and prevent the polarizing film from being damaged by an external force.

Further, in the present invention, in a rear projection type liquid crystal projector device of the type in which a reflecting mirror is provided between the projection lens and the Fresnel lens, the polarization direction of the light emitted from the projection lens is set to the reflecting mirror. By using S-polarized light, the maximum reflectance of the reflecting mirror can be utilized.

[0029]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a system configuration diagram showing a first embodiment of a rear projection type liquid crystal projector device according to the present invention.

In FIG. 1, the rear projection type liquid crystal projector device 1 is arranged so that a light source lamp 111 serving as a light source, a power supply circuit 113 for supplying power to the light source lamp 111, and the light source lamp 111 are located at a focal point. Parabolic mirror 1
15, a UV / IR filter 117 that cuts ultraviolet rays and infrared rays, dichroic mirrors 121, 123, 133 and 135, total reflection mirrors 125 and 131 that form color separation / combination means, and an optical path for each color-separated color. Liquid crystal panels 141, 143, 145 provided and a polarizing plate 1 serving as a polarizer provided on the light incident side of each liquid crystal panel.
51, 153, 155 and polarizing plates 161, 163, 165 serving as analyzers provided on the light emission side of each liquid crystal panel.
And a projection lens 171 for enlarging and projecting the color-combined light, a Fresnel lens 175 and a lenticular lens 177 serving as a screen, and a lenticular lens 1
The polarizing film 13 provided outside 77, a video input terminal 181 to which a video signal is input, a signal processing circuit 183 that generates a drive signal for driving the liquid crystal panels 141, 143 and 145 from the video signal, and a green Polarizing plates 155 and 16 provided before and after the liquid crystal panel 145 inserted in the optical path.
And a displacement mechanism 15 for displacing 5.

The operation of the rear projection type liquid crystal projector device 1 of the first embodiment is as follows. First, the light source lamp 111 using a halogen lamp, a metal halide lamp, or the like emits light by receiving a predetermined power supply from the power supply circuit 113. The light emitted from the light source lamp 111 is controlled and reflected by the parabolic mirror 115 into substantially parallel light emitted in the right direction. Then, from the substantially parallel light obtained from the parabolic mirror 115, the UV / IR filter 117 cuts wavelengths in the ultraviolet and infrared regions that are unnecessary and harmful for image formation.

Next, 45 ° with respect to the optical path of the substantially parallel light.
With the dichroic mirrors 121 and 123 forming a part of the color separation / combination means arranged at an angle of,
The light paths of the three primary colors of light are separated in the order of B, R, and G.

That is, first, the dichroic mirror 1
B is reflected and separated by 21 and then R is reflected and separated by the dichroic mirror 123. The remaining G enters the liquid crystal panel 145 via the polarizing plate 155.

B is reflected by the total reflection mirror 131 and enters the liquid crystal panel 141 through the polarizing plate 151. R is incident on the liquid crystal panel 143 via the polarizing plate 153. The B, R, and G lights to which the liquid crystal panels 141, 143, and 145 are provided with the optical rotatory power corresponding to the video signals, are polarizing plates 161, 163, which are analyzers provided on the emission side of the respective liquid crystal panels. After the rotatory spatial distribution is converted into a light intensity spatial distribution by 165, color combination is performed and the light is incident on the projection lens 171.

In the process of color combination, first, B and R are combined by the dichroic mirror 133, and then G reflected by the total reflection mirror 125 is dichroic mirror 1.
Added by 35. The light carrying the color-combined image is incident on the projection lens 171, and the projection lens 1
71 to Fresnel lens 175, lenticular lens 1
The image is enlarged and projected toward the back surface of the screen composed of 77 and the polarizing film 13.

The Fresnel lens 175 is the projection lens 17
The light emitted from the light source 1 is focused on the observation position, and the lenticular lens 177 controls and / or diffuses the light passing through the Fresnel lens 175 in an arbitrary direction. Polarizing film 1
3 has the same polarization direction as that of the polarizing plate 161.

On the other hand, based on the video signal input to the video input terminal 181, the signal processing circuit 183 generates a drive signal for controlling the optical rotatory power of each cell of the liquid crystal panels 141, 143 and 145, and these liquid crystals are generated. Supplied to the panel.

The rear projection type liquid crystal projector device 1 is housed in a housing in which the front surface of the polarizing film 13 is exposed, and an image is observed from the right side of the polarizing film 13 by an observer having a viewpoint 191. It

FIG. 2 is a sectional view for explaining the details of the screen structure in the first embodiment. FIG. 2 (a)
Shows a configuration in which a Fresnel lens 175, a lenticular lens 177, a polarizing film 13 and an acrylic plate 11 as a light transmitting plate having an arbitrary transmittance are arranged in the order of image projection direction.

That is, in FIG. 2A, an arbitrary transmittance (for example, 80) is provided outside the lenticular lens 177.
%) Is provided, and the acrylic plate 1 is provided.
A polarizing film 13 made of iodine or the like, which has a high transmittance and a high degree of polarization among the polarizing plates, is attached to the inner surface of 1.
According to this configuration, the polarizing film 13 is protected by the outer acrylic plate 11, which is preferable from the viewpoint of the durability of the screen.

Further, according to the configuration of FIG. 2B, the Fresnel lens 175, the lenticular lens 177, the acrylic plate 11 as a light transmitting plate having an arbitrary transmittance, and the polarizing film 13 are arranged in the order of the image projection direction. are doing. According to this configuration, the efficiency of cutting the external light by the polarizing film 13 is the highest, but the configuration of FIG. 2A is more excellent in terms of protection of the polarizing film.

The polarizing film 13 can be arranged at any position from the projection lens 171 to the outside of the lenticular lens 177, but it does not pass through the liquid crystal panel or the dispersion characteristics of the Fresnel lens 175 and the lenticular lens 177. Depending on the state of stray light entering the screen, it may be provided on the incident surface side of the Fresnel lens 129 as shown in FIG. 2C or between the Fresnel lens 129 and the lenticular lens 131 as shown in FIG. 2D. Good.

FIG. 3 illustrates the details of the displacement mechanism 15.
It is a front view (a)-(c) and a transmission characteristic explanatory view (d). In the first embodiment, the polarizing plate 1 which is a polarizer and an analyzer of the liquid crystal panel 145 that carries green light.
The displacement mechanism 15 is provided at 55 and 165. That is, the displacement mechanism 15 that rotates the polarizing plates 155 and 165 with respect to the liquid crystal panel 145 while maintaining the mutual positional relationship is illustrated.

According to the three views of FIGS. 3 (a) to 3 (c), the polarizing plate holder 33, the height adjusting screw 35, the coil spring 37, and the fixing member are fixed to the liquid crystal panel 145 standing on the optical stand 31. The displacement mechanism 15 consisting of screws 39 is shown.

The polarizing plate holder 33 has a tubular shape with a substantially rectangular cross section, a polarizing plate 155 which is a polarizer is provided on the front surface thereof, and a polarizing plate 165 which is an analyzer is provided on the rear surface thereof. . In addition, at the four corners of the front surface of the polarizing plate holder 33, there are arc-shaped elongated holes 3 which are part of a circle centered on the optical axis.
3-1 is provided and is attached to the liquid crystal panel 145 so as to be rotatable around the optical axis by the fixing screw 39.

The height adjusting screw 35 is hung downward through a hole 41-1 of a pedestal 41 provided in the upper right portion of the liquid crystal panel 145, and its tip is provided downward from the upper right portion of the polarizing plate holder 33. It is screwed into the formed screw hole 33-2. A compressed coil spring 37 is arranged around the center of the height adjusting screw 35 between the lower surface of the base 41 and the polarizing plate holder.

By rotating the height adjusting screw 35 to the right or left, the upper right portion of the polarizing plate holder 33 is pulled up or pushed down.
3 can rotate left or right with respect to the optical axis. When the polarizing plate holder 33 rotates, both the polarizer 155 and the analyzer 165 rotate from the reference polarization direction (= polarization direction of the polarization film) by the same angle θ.

Due to this rotation, the emission characteristics of the liquid crystal panel including the analyzer become a curve indicated by the solid line in FIG. 3D, and deviate by an angle θ from the polarization direction of the polarizing film 13 indicated by the broken line. Therefore, the combined transmission characteristic becomes a characteristic shown by the shaded portion.

Next, a method of adjusting the color tone of the color display image using the displacement mechanism 15 will be described. First, a test pattern serving as a reference for color adjustment is input to the rear projection type liquid crystal projector device and displayed. Next, the displayed image is read by a color adjusting device, and the color tone of the image is displayed on, for example, an XYZ color system chromaticity diagram. Then, by adjusting the height adjusting screw of the polarizing plate displacement mechanism provided on the liquid crystal panel, the transmitted light intensity of the liquid crystal panel having the excessive intensity read from this chromaticity diagram can be adjusted to an appropriate level. The intensity is adjusted to obtain an image having a desired color tone.

Although the displacement mechanism is applied to the polarizer and the analyzer corresponding to the liquid crystal panel inserted in the green optical path in the first embodiment, the present invention is not limited to this. , May be applied to a polarizer and an analyzer corresponding to a liquid crystal panel inserted in an optical path of another color,
Further, a plurality of displacement mechanisms may be provided, and the color tone may be adjusted by displacing the respective polarizers and analyzers as a pair with respect to the plurality of liquid crystal panels.

FIG. 4 is a trihedral view and a transmission characteristic explanatory view for explaining a modified example of the displacement mechanism. According to the three views of FIGS. 4A to 4C, the polarizer holder 33, the height adjusting screw 35, the coil spring 37, the fixing screw 39, and The displacement mechanism 17 including the link member 43 is shown.

The polarizing plate holder 33 has a tubular shape with a substantially rectangular cross section, a polarizing plate 155 as a polarizer is provided on the front surface thereof, and a polarizing plate 165 as an analyzer is provided on the rear surface thereof. . On the left side of the front surface of the polarization plate holder 33, a hole 33-1 which is the center of the inclination is provided, and the fixing screw 39
Is rotatably attached to the liquid crystal panel 145. Further, an arc-shaped elongated hole 33-2 which is a part of a circle centered on the hole 33-1 is provided on the upper right side and the lower side of the front surface of the polarizing plate holder 33, and can be rotated by a fixing screw 39. It is attached to the liquid crystal panel 145 as described above.

The height adjusting screw 35 is hung vertically downward through the hole 41-1 of the pedestal 41 provided in the upper right portion of the liquid crystal panel 145, and the tip end portion thereof is the link member 43 fixed to the polarizing plate holder 33. Is screwed into the screw hole 43-1.

The link member 43 has a flange 43 at the upper end.
-3 and a pin 43-5 rotatably connected to the polarizing plate holder 33 at the lower end. A compressed coil spring 37 is arranged around the height adjusting screw 35 between the lower surface of the base 41 and the flange 43-1.

Then, by rotating the height adjusting screw 35 to the right or left, the link member connecting portion of the polarizing plate holder 33 is pulled up or pushed down, so that the polarizing plate holder 33 is moved relative to the optical axis of the liquid crystal panel 145. It can be tilted left or right. When the polarizing plate holder 33 is tilted, the polarizer and the analyzer both have the same angle θ as the reference polarization direction (= polarization direction of the polarization film).
Will lean from. The displacement mechanism 15 of FIG. 3 rotates the polarizing plate with respect to the optical axis of the liquid crystal panel, while the displacement mechanism 15 of FIG.
The displacement mechanism 17 has a polarizing plate tilted with respect to the optical axis of the liquid crystal panel, but there is no way to shift the polarization direction from the reference polarization direction by an angle θ, and like the displacement mechanism 15, it is possible to adjust the color tone. Available.

FIG. 5 is a system configuration diagram showing a second embodiment of a rear projection type liquid crystal projector device according to the present invention. In the figure, a rear projection type liquid crystal projector device 2 includes a light source lamp 111 serving as a light source and a light source lamp 1.
11, a power source circuit 113 for supplying power to the power source 11, an ellipsoidal mirror 114 arranged so that the light source lamp 111 is located at one focus, a UV / IR filter 117 for cutting ultraviolet rays and infrared rays, and an ellipsoidal mirror 114. And a dichroic mirror 121, 123, 1 which constitutes a color separation / combination means.
33 and 135, total reflection mirrors 125 and 131, and a liquid crystal panel 141 provided for each color-separated optical path of each color.
143 and 145, polarizing plates 151, 153 and 155 which are polarizers provided on the light incident side of each liquid crystal panel, and a polarizing plate 161 which is an analyzer provided on the light emitting side of each liquid crystal panel, 163 and 165, a projection lens 171 for enlarging and projecting the color-combined light incident thereon, a Fresnel lens 175 and a lenticular lens 17 forming a screen.
7 and the polarizing film 13, a video input terminal 181 to which a video signal is input, and a signal processing circuit 18 that generates a drive signal for the liquid crystal panels 141, 143, and 145 from the video signal.
3 and polarizing plates 155 and 165 inserted in the green optical path.
And a displacement mechanism 15 for displacing the.

The operation of the rear projection type liquid crystal projector device 2 of the second embodiment is as follows. First, the light source lamp 111 using a halogen lamp, a metal halide lamp, or the like emits light by receiving a predetermined power supply from the power supply circuit 113. Light emitted from the light source lamp 111 arranged at one focus of the ellipsoidal mirror 114 is reflected rightward by the ellipsoidal mirror 114, and UV / IR filter 117 has wavelengths in the ultraviolet and infrared regions which are unnecessary and harmful for image formation. The light is cut by the condenser lens 116 and is converged by the condenser lens 116 into substantially parallel light.

Next, 45 ° with respect to the optical path of the substantially parallel light.
With the dichroic mirrors 121 and 123 forming a part of the color separation / combination means arranged at an angle of,
The light paths of the three primary colors of light are separated in the order of B, R, and G.

That is, first, the dichroic mirror 1
B is reflected and separated by 21 and then R is reflected and separated by the dichroic mirror 123. The remaining G enters the liquid crystal panel 145 via the polarizing plate 155.

B is reflected by the total reflection mirror 131 and enters the liquid crystal panel 141 via the polarizing plate 151. R is incident on the liquid crystal panel 143 via the polarizing plate 153. The B, R, and G lights to which the liquid crystal panels 141, 143, and 145 are provided with the optical rotatory power corresponding to the video signals, are polarizing plates 161, 163, which are analyzers provided on the emission side of the respective liquid crystal panels. After the rotatory spatial distribution is converted into a light intensity spatial distribution by 165, color combination is performed and the light is incident on the projection lens 171.

In the process of color combination, first, B and R are combined by the dichroic mirror 133, and then G reflected by the total reflection mirror 125 is dichroic mirror 1.
Added by 35. The light carrying the color-combined image is incident on the projection lens 171, and the projection lens 1
71 to Fresnel lens 175, lenticular lens 1
The image is enlarged and projected toward the back surface of the screen composed of 77 and the polarizing film 13.

The Fresnel lens 175 is the projection lens 17
The light emitted from the light source 1 is focused on the observation position, and the lenticular lens 177 controls and / or diffuses the light passing through the Fresnel lens 175 in an arbitrary direction. Polarizing film 1
3 has the same polarization direction as that of the polarizing plate 161.

On the other hand, based on the video signal input to the video input terminal 181, the signal processing circuit 183 generates a drive signal for controlling the optical rotatory power of each cell of the liquid crystal panels 141, 143 and 145, and these liquid crystals are generated. Supplied to the panel.

The rear projection type liquid crystal projector device 1 is housed in a casing in which the front surface of the polarizing film 13 is exposed, and an image is observed from the right side of the polarizing film 13 by an observer having a viewpoint 191. It

The details of the screen structure in the second embodiment are the same as those in the first embodiment.
Since the configuration shown in (1) is applied as it is, detailed description will be omitted.

Further, the displacement mechanism 1 used in this embodiment
5 is a displacement mechanism similar to the displacement mechanism of FIG. 3 used in the first embodiment, and the displacement mechanism 17 shown in FIG. 4 can also be applied in the same manner, so detailed description will be omitted.

Also in the present embodiment, as in the first embodiment, the polarization component perpendicular to the polarization direction of the polarizing film contained in the external light reflected from the front surface of the lenticular lens can be cut off. It is possible to reduce the reflectance of light and improve the contrast of an image.

In the present embodiment, as in the first embodiment, the pair of polarizer and analyzer of the liquid crystal panel having excessive light intensity is rotated or tilted with respect to the liquid crystal panel by the displacement mechanism. By tilting from the reference polarization direction, the color components carried by the liquid crystal panel can be attenuated, and the color balance can be adjusted without impairing the dynamic range of the color image.

FIG. 6 is a system configuration diagram showing a third embodiment of a rear projection type liquid crystal projector device according to the present invention. In the figure, a rear projection type liquid crystal projector device 3 includes a light source lamp 111 serving as a light source and a light source lamp 1.
11, and a parabolic mirror 115 arranged so that the light source lamp 111 is located at the focal point.
A UV / IR filter 117 that cuts ultraviolet rays and infrared rays, and dichroic mirrors 121, 123, 133, 135 and a total reflection mirror 1 that constitute color separation / combination means.
25 and 131, liquid crystal panels 141, 143, and 145 provided for each color-separated light path of each color, and a polarizing plate 15 serving as a polarizer provided on the light incident side of each liquid crystal panel.
1, 153, 155 and polarizing plates 161, 163, 165 serving as analyzers provided on the light emission side of each liquid crystal panel.
A projection lens 171 for enlarging and projecting the color-combined light, a reflection mirror 179, a Fresnel lens 175 and a lenticular lens 177 serving as a screen, and a polarizing film 13 provided outside the lenticular lens 177.
A video input terminal 181, to which a video signal is input, a signal processing circuit 183 which generates a drive signal for driving the liquid crystal panels 141, 143 and 145 from the video signal, and the front and rear of the liquid crystal panel 145 inserted in the green optical path. And a displacement mechanism 15 for displacing the polarizing plates 155 and 165 provided in the.

The rear projection type liquid crystal projector device 3 of the third embodiment is different from the first embodiment in that the reflection mirror 1 is provided between the projection lens 171 and the Fresnel lens 175.
79 is added, the optical path projected from the projection lens 171 to the screen is bent by the reflecting mirror 179,
That is, the rear projection type liquid crystal projector device 3 is downsized. The operation of the other constituent elements is the same as that of the first embodiment, and detailed description thereof will be omitted.

The feature of the third embodiment is that the polarization directions of the polarizing plates 161, 163 and 165 which are the analyzers are aligned so that the light entering and reflected by the reflecting mirror 179 becomes S-polarized. , The polarization direction of the light projected from the projection lens 171 becomes S-polarized on the reflecting surface of the reflecting mirror 179, and the reflectance Rs of the S-polarized component shown in FIG. 7 is applied.
That is, a reflectance that is always higher than the reflectance Rp of the P-polarized component is obtained.

As a result, the light that is enlarged and projected from the projection lens 171 toward the screen composed of the Fresnel lens 175, the lenticular lens 177 and the polarizing film 13 is reduced in attenuation by the reflection mirror 179, and the contrast is improved brightly. The image is observed from the outside of the polarizing film 13.

[0073]

As described above, according to the present invention, a polarized light having the same polarization direction transmission characteristic as a polarizing plate which is an analyzer is provided at an arbitrary position from the projection lens of the rear projection type liquid crystal projector device to the front surface of the lenticular lens. By further including the film, it is possible to cut the polarization component perpendicular to the polarization direction of the polarizing film included in the external light reflected from the front surface (observation surface) of the lenticular lens, thereby reducing the reflectance of the external light, There is an effect that the contrast of an image can be improved.

Further, according to the present invention, by providing the light transmitting plate having an arbitrary transmittance, it is possible to further improve the contrast of the image.

Further, according to the present invention, a light transmitting plate having an arbitrary transmittance is further provided outside the polarizing film, whereby the contrast of the image is further improved, and
There is an effect that it is possible to prevent the polarizing film from being damaged by an external force.

Further, according to the present invention, the polarizer and the analyzer provided on the entrance side and the exit side of at least one liquid crystal panel are paired with each other while maintaining their mutual positional relationship. Since a displacement mechanism for rotating or tilting the liquid crystal panel is provided, the pair of polarizer and analyzer of the liquid crystal panel having excessive light intensity is rotated or tilted with respect to the liquid crystal panel by the displacement mechanism and tilted from the reference polarization direction. As a result, there is an effect that the color component carried by the liquid crystal panel is reduced, and the color balance can be adjusted without impairing the dynamic range of the color image.

Further, according to the present invention, in the rear projection type liquid crystal projector device of the type in which the reflection mirror is provided between the projection lens and the Fresnel lens, the polarization direction of the light emitted from the projection lens is changed to the reflection mirror. On the other hand, by using S-polarized light, the maximum reflectance of the reflecting mirror can be utilized, and there is an effect that the image can be brightened and the contrast can be improved.

[Brief description of drawings]

FIG. 1 is a system configuration diagram illustrating a first embodiment of a rear projection type liquid crystal projector device according to the present invention.

FIG. 2 is a sectional view illustrating a screen configuration of a rear projection type liquid crystal projector device according to the present invention.

FIG. 3 is a perspective view showing details of a displacement mechanism for rotating a polarizer and an analyzer of the rear projection type liquid crystal projector device according to the present invention.

FIG. 4 is a perspective view showing details of a displacement mechanism for inclining a polarizer and an analyzer of the rear projection type liquid crystal projector device according to the present invention.

FIG. 5 is a system configuration diagram illustrating a second embodiment of a rear projection type liquid crystal projector device according to the present invention.

FIG. 6 is a system configuration diagram illustrating a third embodiment of a rear projection type liquid crystal projector device according to the present invention.

FIG. 7 is a graph showing respective reflectances of S-polarized light and P-polarized light.

FIG. 8 is a system configuration diagram illustrating a configuration example of a conventional rear projection type liquid crystal projector device.

[Explanation of symbols]

1 ... Rear projection type liquid crystal projector device, 13 ... Polarizing film,
15 ... Displacement mechanism, 111 ... Light source lamp, 113 ... Power supply circuit, 115 ... Parabolic mirror 117 ... UV / IR filter, 121, 123, 133, 135 ... Dichroic mirror, 125, 131 ... Total reflection mirror, 141, 14
3, 145 ... Liquid crystal panel, 151, 153, 155 ... Polarizing plate (polarizer), 161, 163, 165 ... Polarizing plate (analyzer), 171 ... Projection lens, 175 ... Fresnel lens, 177 ... Lenticular lens, 181 ... Image input terminal, 183 ... Signal processing circuit.

[Procedure amendment]

[Submission date] April 8, 1996

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

[Fig. 2]

FIG. 7

[Figure 3]

FIG. 4

[Figure 5]

FIG. 6

[Figure 8]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshimitsu Umezawa 1-9-2 Harara-cho, Fukaya-shi, Saitama Prefecture Fukaya Plant, Toshiba Corporation (72) Yutaka Saito 1-9-2 Hara-cho, Fukaya-shi, Saitama Shares Company Toshiba Fukaya Factory (72) Inventor Toshio Obayashi 1-9-2 Hararacho, Fukaya City, Saitama Prefecture Toshiba Fukaya Factory

Claims (5)

[Claims] 1. A light source lamp, a parabolic mirror that controls and reflects light emitted from the light source lamp into substantially parallel light, and substantially parallel light obtained from the parabolic mirror using a dichroic mirror and a total reflection mirror. And a plurality of liquid crystals arranged in a matrix, each of which is provided in each of the paths of the light separated into the three primary colors. Three liquid crystal panels provided with cells, a polarizer provided on each light incident side of each of these liquid crystal panels, an analyzer provided on each light emission side of each of these liquid crystal panels, A projection lens that magnifies and projects the color-combined light, a Fresnel lens that condenses the light emitted from this projection lens at an arbitrary position, and the light that has passed through this Fresnel lens is controlled and / or expanded in an arbitrary direction. In a rear projection type liquid crystal projector device comprising: a lenticular lens, and a polarizing film having the same polarization direction transmission characteristic as that of the analyzer, which is arranged at an arbitrary position from the projection lens to the front surface of the lenticular lens. A displacement mechanism for rotating or tilting with respect to the liquid crystal panel while maintaining the mutual positional relationship with the polarizer and the analyzer provided as a pair on the incident side and the emitting side of at least one liquid crystal panel, A rear projection type liquid crystal projector device characterized by being provided. 2. A light source lamp, an ellipsoidal mirror for reflecting and condensing light emitted from the light source lamp, and a condenser lens for making light emitted from the ellipsoidal mirror substantially parallel to the optical axis. A color separation / combination means for separating substantially parallel light obtained from the condenser lens into different paths for each of the three primary colors of light by using a dichroic mirror and a total reflection mirror, and then recombining them, and is decomposed into these three primary colors. Three liquid crystal panels provided for each light path, each of which has a plurality of liquid crystal cells arranged in a matrix, and a polarizer provided on each light incident side of each of these liquid crystal panels, An analyzer provided on each light emission side of the liquid crystal panel, a projection lens for enlarging and projecting the color-combined light, and a Fresnel lens for condensing the light emitted from the projection lens at an arbitrary position. , In a rear projection type liquid crystal projector device comprising a lenticular lens for controlling and / or diffusing light passing through this Fresnel lens in an arbitrary direction, the rear projection type liquid crystal projector device is arranged at an arbitrary position from the projection lens to the front surface of the lenticular lens. A polarization film having the same polarization direction transmission characteristics as the analyzer, and a polarizer and the analyzer provided on the incident side and the emission side of at least one liquid crystal panel as a pair, while maintaining a mutual positional relationship, A rear projection type liquid crystal projector device further comprising a displacement mechanism for rotating or tilting the liquid crystal panel. 3. The polarizing film is arranged outside the lenticular lens, and a light transmitting plate having an arbitrary transmittance is further provided outside the polarizing film. Rear projection type liquid crystal projector device according to the item. 4. The polarizing film is arranged outside the lenticular lens, and a light transmitting plate having an arbitrary transmittance is further provided between the lenticular lens and the polarizing film. Alternatively, the rear projection type liquid crystal projector device according to claim 2. 5. A reflection mirror is further provided between the projection lens and the Fresnel lens, and a polarization direction of light emitted from the projection lens is S polarization with respect to the reflection mirror. The rear projection type liquid crystal projector device according to any one of claims 1 to 4.